Recording medium having spare area for defect management and information on defect management, and method of allocating spare area and method of managing defects

ABSTRACT

A recording medium having a spare area for defect management and the management information of the spare area, a spare area allocation method, and a defect management method. When a primary spare area is allocated for slipping replacement and linear replacement upon initialization, and a remaining portion of the primary spare area after slipping replacement and allocated for linear replacement after initialization are insufficient, a supplementary spare area is allocated. The sizes of the primary and supplementary spare areas are determined by the number of defects generated upon initialization. The information on the sizes of the spare areas, and the remainder state information representing the degree of use of the spare areas, are recorded, so that the spare areas can be efficiently managed. Also, in the defect management method, when an area that has already been linearly replaced is allocated as a supplementary spare area, defective blocks within the allocated supplementary spare area are not used for linear replacement, and the entries of a secondary defect list (SDL) with respect to the defective blocks are not changed.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a divisional of application Ser. No.09/986,307, which is a divisional of application Ser. No. 09/635,667,which is a divisional of parent application Ser. No. 09/437,451, andclaims the benefit of Korean Application No. 98-48008, filed Nov. 10,1998 and Korean Application No. 99-4678, filed Feb. 10, 1999, in theKorean Patent Office, the disclosures of which are incorporated hereinby reference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to the field of optical recordingmedia, and more particularly, to a disc having information on the sizesof allocated spare areas and the remaining amounts thereof, in which anappropriate amount of a primary spare area is allocated uponinitialization, and a supplementary spare area is allocated if theprimary spare area is insufficient while being used after completion ofinitialization, a method of allocating the spare areas, and a method ofmanaging the defects of the primary and supplementary spare areas.

[0004] 2. Description of the Related Art

[0005] In recording media such as general discs, a spare area isallocated once upon initialization and no supplementary spare area isallocated during use of the disc. However, in order to increase theefficiency of using a disc, an appropriate amount of spare area isallocated according to the state of the disc upon initialization, and asupplementary spare area is allocated when the spare area allocated uponinitialization is insufficient while the disc is being used.

[0006] According to a digital versatile disc random access memory(DVD-RAM) standard (DVD Specifications for Rewritable Disc, Part 1PHYSICAL SPECIFICATIONS) version 1.0, each zone has one spare area, sothat 24 spare areas are allocated upon initialization since a disc has24 zones.

[0007] In the related art, as shown in FIG. 1, a flag representing thestate of the spare area allocated to each zone within a defectmanagement area (DMA) is constituted of only one bit, which representswhether or not a corresponding spare area can be used, i.e., whether itis occupied. Accordingly, a full spare area flag has 24 bits ofinformation representing whether or not 24 spare areas are occupied.Also, this full spare area flag is stored in relative byte positions(RBP) 8 to 15 of a secondary defect list (SDL) of the DMA. When a bitrepresenting a corresponding group is “1”, this represents that no sparearea remains within the corresponding group, and when the bit is “0”,this represents that a spare area remains within the correspondinggroup.

[0008] Information on a spare area, which is constituted of only one bitas described above, represents only whether the spare area is occupied.On the other hand, in discs in which a supplementary spare area can beallocated after initialization, it is preferable that the supplementaryspare area is allocated on a disc when the spare area has some room in astate of being almost occupied rather than when the spare area iscompletely occupied. However, a problem occurs in that the state inwhich the spare area is almost occupied cannot be represented by onlythe one bit.

[0009] Also, in the allocation of spare areas according to the existingDVD-RAM standard version 1.0, a predetermined amount of spare area isallocated to each zone upon initialization, the size of which ispredetermined to be sufficient to process all defects that can bemanaged by a defect management method that is applied to a correspondingdisc.

[0010] Here, in order to manage defects on a generalrecordable/rewritable disc, a slipping replacement method of skippingdefects without providing logical sector numbers to the defects, is notused for defects generated upon initialization of the disc, which arecalled “primary defects” It is prescribed in the existing DVD-RAMstandard version 1.0 that the position of a defective sector replaced byslipping replacement must be recorded in a primary defect list (PDL) ina DMA on a disc. Also, linear replacement for replacing error correctioncode (ECC) blocks of an erroneous zone with normal blocks in a sparearea, is used for defects generated during use of the disc, which arecalled “secondary defects.” It is prescribed in the existing DVD-RAMstandard version 1.0 that the position of a defective block replaced bylinear replacement must be recorded in an SDL in a DMA on a disc.

[0011] However, when an appropriate amount of spare area is allocatedaccording to the state of a disc upon initialization, and asupplementary spare area is allocated as the state of the disc becomesbad during use of the disc (“bad” meaning that the more the disc isused, the more defects it has), a more effective spare area allocatingmethod is required. It is prescribed in the existing standard that in arecording and/or reproducing apparatus of a disc, the size of a bufferfor temporarily storing defect management information existing on a discis 32 Kbytes. Accordingly, a restriction is generated in that the actualnumber of defects that can be managed becomes less than the number ofdefects that can be recorded in the DMA on the disc.

[0012] Here, the defect management information includes PDL and SDL, andthe sum of the sizes of the PDL and SDL is about 60 Kbytes. Thus, in theDVD-RAM standard version 1.0, PDL ranges from sectors 1 to 15, and theremaining sectors are set to be used to process SDL entries, so that thenumber of PDL entries and SDL entries that can be processed isrestricted in accordance with the size (32 Kbytes) of a buffer of arecording and/or reproducing apparatus.

SUMMARY OF THE INVENTION

[0013] To solve the above problems, an object of the present inventionis to provide a recording medium having information associated with thesize and the remaining amount of a spare area allocated uponinitialization, and with the size and the remaining amount of a sparearea allocated after initialization.

[0014] Another object of the present invention is to provide a method ofsimply calculating and allocating a spare area for slipping replacementand a spare area for linearly replacing some defects, while a disc isbeing initialized, and a spare area for linear replacement which isrequired during use of the disc.

[0015] Still another object of the present invention is to provide amethod of managing defects in a supplementary spare area which isallocated for linear replacement while the disc is being used.

[0016] Additional objects and advantages of the invention will be setforth in part in the description which follows and, in part, will beobvious from the description, or may be learned by practice of theinvention.

[0017] To achieve the first and other objects, the present inventionprovides a recording medium such that a primary spare area is allocatedupon initialization and a supplementary spare area is allocated afterinitialization, and the sizes of the spare areas are determined by thenumber of defects generated upon initialization.

[0018] To achieve the second and other objects, the present inventionprovides a method of allocating a total spare area to manage defects ina disc recording and/or reproducing apparatus, the method includingdetermining the minimum size of the total spare area using the number ofprimary defects generated during initialization; determining the maximumsize of the total spare area that must be allocated according to thesize of a memory device for defect management of the disc recordingand/or reproducing apparatus; and allocating a primary spare area forslipping replacement and linear replacement using the minimum andmaximum sizes of the total spare area.

[0019] To achieve the third and other objects, the present inventionprovides a defect management method for a disc recording and/orreproducing apparatus having a primary spare area allocated to replaceprimary defects generated during initialization using slippingreplacement, and a supplementary spare area allocated to replacesecondary defects generated after initialization using linearreplacement, the method comprising allocating the supplementary sparearea using an area that has already been linearly replaced, whereindefective blocks within the supplementary spare area which has alreadybeen linearly replaced are not used for linear replacement, and SDLentries within a defect management area with respect to the defectiveblocks are not changed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above and other objects and advantages of the presentinvention will become more apparent by describing in detail preferredembodiments thereof with reference to the attached drawings, in which:

[0021]FIG. 1 is a view illustrating the structure of a conventional fullspare area flag having SDL contents;

[0022]FIG. 2 is a view illustrating the structure of a disc having auser area, a primary spare area and a supplementary spare area,according to the present invention;

[0023]FIGS. 3A and 3B are views illustrating methods of managing adefect generated on a supplementary spare area in the structure of thedisc shown in FIG. 2;

[0024]FIGS. 4A and 4B are tables showing allocation of a primary sparearea and a supplementary spare area according to the present invention,when the size of a buffer for defect management in a disc recordingand/or reproducing apparatus is 32 Kbytes and 64 Kbytes, respectively;

[0025]FIGS. 5A and 5B are views illustrating the structures of a flag ofremainder state information which represents the degree to which a sparearea for managing defects has been used, according to the presentinvention;

[0026]FIG. 6 is a flowchart illustrating a method of allocating primaryand supplementary spare areas upon initialization, according to thepresent invention;

[0027]FIG. 7 is a flowchart illustrating a method of allocating a (aninitial) supplementary spare area using remainder state information of aprimary spare area, according to the present invention; and

[0028]FIG. 8 is a flowchart illustrating a method of allocating ananother supplementary spare area using remainder state information of aninitial supplementary spare area, according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] Spare areas on a disc for defect management according to thepresent invention include a primary spare area and one or moresupplementary spare areas.

[0030] The primary spare area is first allocated for defect replacementwhen a disc is initialized, and is first used for slipping replacement.The primary spare area remaining after slipping replacement can also beused for linear replacement. The supplementary spare area, for linearlyreplacing defects generated while the disc is being used, denotes aspare area which is additionally allocated while a disc is being usedafter it has been initialized.

[0031] That is, in the present invention as shown in FIG. 2, a primaryspare area for slipping replacement and linear replacement is allocatedon a disc during initialization of the disc. The slipping replacementperforms replacement in units of sectors, thus increasing the efficiencyof utilization of the spare area. However, in the slipping replacement,defective areas are merely not used, and data starts being recorded inthe next normal data sector, so that the defective areas cannot be usedafter initialization.

[0032] The primary spare area must have a minimum spare area necessaryfor slipping replacement and a predetermined amount of spare area forlinearly replacing defects that can be generated on a disc while thedisc is being used. Here, the portion of the primary spare area forslipping replacement requires at least as many sectors as the number ofentries registered in a PDL among defect management information.

[0033] Supplementary spare areas of predetermined sizes are allocated ina forward direction from the rearmost portion of a same logical filearea when the primary spare area is insufficient to process secondarydefects generated during use of the disc after initialization.

[0034] In the present invention, a direct pointing rule is also appliedas a defect management method for spare areas proposed by the DVD-RAMstandard version 1.0. That is, all defects must be processed by only onereplacement.

[0035] An extensible supplementary spare area allocated for linearreplacement after initialization could have been already used as a userdata area. That is, a defective block, which is used as a user dataarea, is allocated as a supplementary spare area, and it could belinearly replaced by a primary spare area or a supplementary spare areawhich has already been allocated, as shown in FIG. 3A. When a spare areawhich has already been linearly replaced is intended to be used as asupplementary spare area, dual replacement of a defect in another userarea by a defective block already linearly replaced within thesupplementary spare area violates the direct pointing rule. Also, inread-only discs, the process of replacement is complicated.

[0036] To solve these problems, as shown in FIG. 3B, a defective blockwithin the supplementary spare area that has already been linearlyreplaced by a primary spare area or a pre-allocated supplementary sparearea as shown in FIG. 3B, must not be used for linear replacement. Also,secondary defect list (SDL) entries for a corresponding defective blockstored in a defect management area must not be changed. The reason whythe SDL entries must not be changed is that a portion of the spare area,which is skipped and not used while the spare area is being sequentiallyused, is determined to be a defective area if the SDL entries used toprocess defects with a supplementary spare area are erased. Thus, anormal block used for linear replacement can be misdetermined as adefect, and thus, when formatting is performed later, a non-defectiveportion can be registered as a defect. Therefore, SDL entry informationwith respect to a linearly-replaced defective block within thesupplementary spare area is not changed, and the corresponding defectiveblock must not be used to linearly replace a defect within a user area.

[0037] In disc recording and/or reproducing apparatuses, information ona disc is initially read by a temporary storage area such as asemiconductor memory, that is, a buffer, in order to immediately usedefect management information. It is prescribed in the DVD-RAM standardversion 1.0 that a 32 Kbyte-size buffer is used. 32 Kbytes correspond toinformation for 16 sectors, and PDL and SDL for defect managementinformation are stored in the buffer in units of sectors. Thus, theminimum number of PDL entries stored in the buffer is for one sector,and the maximum number of PDL entries stored in the buffer correspond tothe maximum number of entries (i.e., 7679 entries which are for 15sectors) that can be recorded in the PDL. The entries of the SDL occupyan area remaining after PDL entries are stored in the 32 Kbyte buffer,and thus can manage defect entries which have a size ranging from aminimum of one sector to a maximum of 15 sectors.

[0038] Hence, the maximum allowable size of a total spare area (all ofthe spare areas, or in other words, a primary spare area+a supplementaryspare area) is determined by the size of a buffer and the number of PDLentries generated upon initialization of a disc. Here, since a defectcan probably be generated even in the spare area, an extra spare areafor the possible defect must be considered.

[0039] In the present invention, a 60 Kbyte buffer that can store defectinformation associated with defects having a size of 30 sectors can beused to completely process the maximum number of entries (7679 entries:for 15 sectors) that can be recorded in the PDL and the maximum numberof entries (3837 entries: for 15 sectors) that can be recorded in theSDL.

[0040] Also, if a buffer is set to have a 64 Kbyte size, the 64 Kbytebuffer can process as many defects as can be recorded in the defectmanagement information area according to the standard. In an embodimentof the present invention, the most preferable sizes of the spare areasthat can be allocated during initialization of a disc and during use ofthe disc are proposed with respect to a case in which a buffer fordefect management is of 32 Kbytes and a case in which a buffer fordefect management is of 64 Kbytes.

[0041] If the size of a spare area that can be allocated is restrictedso as to have a predetermined amount of increment, a calculationexpression for calculating a required amount of spare area can begreatly simplified as described later. In consideration of this merit, aspare area for slipping replacement for managing primary defects iscalculated by dividing PDL entries in units of sectors. 512 PDL entriescorrespond to one sector, and the amount of a spare area for processing512 PDL entries corresponds to 32 ECC blocks. One ECC block has 16 datasectors.

[0042]FIGS. 4A and 4B are tables showing the size of spare areas whenthe size of the buffer is 32 Kbytes and 64 Kbytes, respectively. Thefirst column in each of FIGS. 4A and 4B represents the number of PDLentries, and the second column therein shows the maximum number of SDLentries, that can be processed, with respect to the number of thecorresponding PDL entries. The numerals in the third column denote theminimum sizes of spare areas, which are expressed in ECC blocks,required if a spare area for defect management entries for linearreplacement of one sector is allocated. That is, the minimum size of thespare area that can be allocated is the sum of all spare areas requiredto process the PDL entries with a spare area required to process the SDLentries for one sector.

[0043] The next column shows the minimum size of spare areas required toprocess all defects under a corresponding defect condition. The firstsubcolumn in the fourth column shows the minimum size of required spareareas in blocks, the second subcolumn shows the minimum size of requiredspare areas in mega bytes (MB), and the third subcolumn shows theminimum size of required spare areas as a percentage (%) of the entirecapacity. The next column shows the total number of defect entries thatcan be processed. The last column shows the maximum amount of a sparearea recommended by the present invention, that is, the amount of sparearea simplified in consideration of an appropriate amount ofsupplementary spare area to facilitate calculation of the amount of thespare area and replace defects generated in the spare area. In the lastcolumn, the first and second subcolumns show the maximum size ofrecommended spare areas in blocks and the percentage of the spare areato the total recording capacity of a disc, respectively, when theincrement between required spare areas is set to be 32 blocks, The thirdand fourth subcolumns show the maximum size of recommended spare areasin blocks and the percentage of the spare area with respect to the totalrecording capacity of a disc, respectively, when the increment betweenrequired spare areas is set to be 48 blocks,

[0044] As shown in FIG. 4A, when a 32 Kbyte buffer is used, all defectsthat can be recorded in all defect management areas cannot be completelyprocessed. As the number of primary defects (PDL entries) increases, theactual number of secondary defects that can be processed decreases, andthe percentage of the total spare area also decreases. This means thatthe state of a disc becomes worse as the number of primary defectsincreases, which reduces the number of secondary defects that can bemanaged.

[0045] To solve this problem, referring to FIG. 4B, the presentinvention recommends using a 64 Kbyte buffer. In this case, a maximumnumber of secondary defects that can be recorded in a defect managementarea can be completely processed regardless of the number of primarydefects. Also, the amount of total spare area can be kept relativelyconstant from about 2.7% to 3%.

[0046] The present invention describes a disc in which a primary sparearea for defect management is partially allocated upon initializationaccording to the usage purpose of the disc or the state of the disc, anda supplementary spare area is allocated after initialization when thesize of the spare area is insufficient. Accordingly, when thesupplementary spare area must be allocated, the amount of asupplementary spare area that can be allocated must be calculated inadvance. That is, the supplementary spare area can be easily allocatedby recording the size of a supplementary spare area that can beallocated in a disc definition structure (DDS) of the defect managementarea (DMA), upon initialization.

[0047] The size of a total spare area for defect management can besimply calculated as described below. When the 64 Kbyte buffer is used,the maximum size of a total spare area that can be allocated can becalculated by the following Equation 1:

maximum size of total spare area${{maximum}\quad {size}\quad {of}\quad {total}\quad {spare}\quad {area}} = {{\left\lbrack \frac{E_{PDL}}{512} \right\rbrack \_ 32} + {4096\quad {blocks}}}$

[0048] blocks

maximum size of total spare area${{maximum}\quad {size}\quad {of}\quad {total}\quad {spare}\quad {area}} = {{4096 \cdot \left\lbrack \frac{E_{PDL}}{512} \right\rbrack}\_ \left( {256 \cdot 32} \right)\quad {blocks}}$

[0049] blocks

[0050] When the 32 Kbyte buffer is used, the maximum size of a totalspare area that can be allocated can be calculated by the followingEquation 2:

[0051] In Equations 1 and 2,$\left\lbrack \frac{E_{PDL}}{512} \right\rbrack$

[0052] denotes a maximum integer which does not exceed${``\frac{E_{PDL}}{512}"},$

[0053] E_(PDL) denotes the number of PDL entries, and 32(=INC) indicatesan increment. 4096 (=S_(MAX)) is a multiple of 2 in which the size of atotal spare area required to process the maximum number of defects isapproximated for simple calculation, when the number of primary defects(the number of PDL entries) is less than 512. Here, the size of a sparearea is shown in ECC blocks. 256 (=S_(SDL)) denotes the size of a sparearea required to process SDL entries for one sector.

[0054] A maximum total spare area recommended by FIGS. 4A and 4B isabout 4% larger than that an actually-required total spare area. Thesize of the recommended total spare area is determined in considerationof defects generated in the total spare area, and are expressed inmultiples of 2, so that calculation of the size of the total spare areais simplified.

[0055] The remainder obtained by subtracting the size of a primary sparearea allocated upon initialization from the maximum size of arecommended total spare area, is recorded in a DDS as the size of asupplementary spare area that can be allocated, whereby thesupplementary spare area can be easily allocated during use of a disc.

[0056] A supplementary spare area is allocated or the size of thesupplementary spare area must be increased, in case that a primary sparearea allocated upon initialization is completely used and no other spareareas exist or the case when a supplementary spare area is completelyused. When a disc is actually used, defects are highly likely to becontinuously generated. Therefore, it is more preferable that asupplementary spare area is allocated or the size of a supplementaryspare area is increased when a small amount of spare area remains, forexample, when a certain number of blocks remain or 90% of the spare areais used, than that a supplementary spare area is allocated after theallocated spare area is completely used.

[0057] In this case, a remainder state flag representing the degree ofuse of a spare area is required to indicate that a predetermined amountor more of the spare area has been used, rather than representing onlytwo states, in which the spare area has been completely used or thespare area still remains, as in an existing spare area full flag. A flagindicating whether a supplementary spare area has been allocated when apredetermined amount or more of the primary spare area has been used, isalso required. In this case, a flag (which can be referred to asremainder state information for a primary spare area) representing thestate of the primary spare area has such states as shown in thefollowing Table 1, and has a structure shown in FIG. 5A. TABLE 1 flagvalue state 00b a sufficient amount of primary spare area remains 01b apredetermined amount or more of primary spare area has been used, and nosupplementary spare area is allocated 10b a predetermined amount or moreof primary spare area has been used, and a supplementary spare area hasbeen allocated 11b the primary spare area has been completely used

[0058] A flag (which can be referred to as remainder state informationfor a supplementary spare area) representing the state of thesupplementary spare area has states as shown in the following Table 2,and has a structure shown in FIG. 5B. TABLE 2 flag value state 00b asufficient amount of supplementary spare area remains. 01b apredetermined amount or more of supplementary spare area has been used.10b no corresponding state 11b the supplementary spare area has beencompletely used

[0059] Here, the flag of Table 2 can indicate the necessity that thesize of the supplementary spare area must be increased by simplyrepresenting the state in which a predetermined amount or more ofsupplementary spare area has been used. The supplementary spare area isenlarged by allocating at least a predetermined additional amount of asupplementary spare area, and the area adjacent to the currentsupplementary spare area or another area is used to perform thisfunction. When the supplementary spare area is enlarged by allocating apredetermined amount or more of supplementary spare area, the value“01b” of the flag can simply be changed to “00b.” Therefore, in contrastwith the remainder state flag for a primary spare area, the remainderstate flag for a supplementary spare area has only three states.

[0060]FIG. 6 is a flowchart illustrating a method of allocating a totalspare area upon initialization, according to an embodiment of thepresent invention. Referring to FIG. 6, a defective sector detectedduring certification for checking the existence or absence of defects ona disc while the disc is being initialized, is skipped without beingsupplied with a logical sector number, and the logical sector numberwhich was to be assigned to the defective sector is provided to the nextsector, and the position of the defective sector is stored in a PDL, instep S101.

[0061] Next, the required amount of the total spare area is calculatedin step S102. For example, when the number of PDL entries is between3072 and 3583, the minimum size of a total spare area is the sum of allspare areas required to process the PDL entries and a spare arearequired to process SDL entries for one sector, and thus becomes 480 ECCblocks. If a 32 Kbyte buffer is used, and the increment betweennecessary spare areas is 32 blocks, 2752 ECC blocks obtained bycalculation using Equation 2 can be allocated as the maximum size ofspare area.

[0062] When the required amount of total spare area is calculated, aprimary spare area is allocated, in step S103. If the size of theprimary spare area is 512 ECC blocks, a maximum of 224 ECC blocks areused to process the PDL entries, and the remaining blocks are used toprocess the SDL entries. After the primary spare area is allocated, aremainder state flag for the primary spare area is set to an initialstate “00,” in step S104. The maximum size of a supplementary spare areais calculated by subtracting the size of the primary spare area,allocated in step S103, from the maximum size of the total spare areacalculated in step S102, in step S105. For example, the maximum size ofthe supplementary spare area, 2240 ECC blocks, can be calculated bysubtracting 512 ECC blocks of the allocated primary spare area from 2752ECC blocks of the maximum spare area. Information on the size of thesupplementary spare area (e.g., 2240 ECC blocks) and information on theremainder state of the supplementary spare area, are recorded atpredetermined positions in a DDS or DMA area, and initialization isconcluded, in step S106.

[0063]FIG. 7 is a flowchart illustrating a method of allocating asupplementary spare area using information on the remainder state of aprimary spare area, according to an embodiment of the present invention.A determination is made as to whether a remainder state flag for theprimary spare area set during initialization is in a state “01” in whichthe primary spare area has been almost used and a supplementary sparearea has been allocated, in step S201. If the answer to the step S201 isNO, another determination is made as to whether a supplementary sparearea is to be allocated, in step S202. If it is determined in step S202that allocation of a supplementary spare area is required, the size ofthe supplementary spare area is checked, in step S203. That is, themaximum size of a supplementary spare area that can be allocated, andthe maximum size of a supplementary spare area that must be allocated,are checked. The size of the supplementary spare area that must beallocated, can be set by a user, or can be a preset predeterminedincrement.

[0064] The existence of a sufficient amount of continuous empty space atthe rear of a logical file area is checked, in step S204. It isdetermined whether enough empty space exists, in step S205. If enoughempty space exists at the rear of the logical file area, a supplementaryspare area for linear replacement, of a predetermined size, is allocatedstarting from the rearmost portion of the logical file area, in stepS206. Management information for the supplementary spare area, that is,a remainder state flag for the supplementary spare area, is initializedback to “00”, and the information on the size of the supplementary sparearea is updated, in step S207. Then, the process is concluded. When anarea that has already been linearly replaced is allocated as thesupplementary spare area for linear replacement in step S206, adefective block within the supplementary spare area is not used forlinear replacement, and the SDL entries must be kept without change, asdescribed above referring to FIG. 3.

[0065] If a sufficient amount of continuous empty area does not exist atthe rear portion of the logical file area in step S205, empty areas arerearranged in step S208. Preferably, this is done by physically movingthe empty areas. Then, a determination is made as to whether asufficient amount of continuous empty area exists, in step S209. Ifthere is a sufficient amount of continuous empty area, the step S206 forallocating a supplementary spare area is again performed. If the amountof continuous empty area is insufficient even after the rearrangement ofthe empty areas, a message “a supplementary spare area cannot beallocated” is displayed, in step S210. Then, the process is concluded.

[0066]FIG. 8 is a flowchart illustrating a method of allocating anothersupplementary spare area using information on the remainder state of aninitial supplementary spare area, according to an embodiment of thepresent invention. A determination is made as to whether a remainderstate flag for the initial supplementary spare area for replacingsecondary defects generated during use of a disc is in a state “01” inwhich the initial supplementary spare area has been almost used, in stepS301. If most of the initial supplementary spare area has been used,another determination is made as to whether another supplementary sparearea is to be allocated, in step S302. If it is determined in step S302that allocation of another supplementary spare area is required, thesize of the another supplementary spare area is checked, in step S303.That is, the maximum size of a supplementary spare area that can beallocated, and the size of the another supplementary spare area thatmust be allocated, are checked. The maximum size of a supplementaryspare area is determined by subtracting the size of a spare areaallocated upon initialization from the maximum size of the total sparearea. The size of the supplementary spare area that must be allocatedcan be set by a user or can be a preset predetermined increment.

[0067] The existence of a sufficient amount of continuous empty space atthe rear of a logical file area is checked, in step S304. Then, it isdetermined whether the empty space exists, in step S305. If enough emptyspace exists at the rear of the logical file area, another supplementaryspare area for linear replacement, of a predetermined size, is allocatedstarting from the rearmost portion of the logical file area, in stepS306. When an area that has already been linearly replaced is allocatedas the supplementary spare area for linear replacement in step S306, adefective block within the supplementary spare area is not used forlinear replacement, and the SDL entries must be kept without change, asdescribed above referring to FIG. 3.

[0068] After the step S306, management information for the anothersupplementary spare area, that is, a remainder state flag for theanother supplementary spare area, is initialized back to “00”, and thesize of the allocated another supplementary spare area is updated, instep S307. Then, the process is concluded.

[0069] If a sufficient amount of continuous empty area does not exist atthe rear portion of the logical file area in step S305, empty areas arerearranged in step S308. Then, a determination is made as to whether asufficient amount of continuous empty area exists, in step S309. Ifthere is a sufficient amount of continuous empty area, the step S306 forallocating the another supplementary spare area is again performed. Ifthe amount of continuous empty area is insufficient even after therearrangement of the empty areas, a message “a supplementary spare areacannot be allocated” is displayed, in step S310. Then, the process isconcluded.

[0070] As described above, in the present invention, information on thesizes of a primary spare area and a supplementary spare area can becalculated by a simple numerical expression, and information on theremainder states of spare areas is stored and managed, so that the spareareas can be more flexibly and effectively allocated and managed.

[0071] Also, in the present invention, defective blocks within thesupplementary spare area are not used for linear replacement, and SDLentries are not changed, so that malfunction is prevented.

[0072] Although a few preferred embodiments of the present inventionhave been shown and described, it would be appreciated by those skilledin the art that changes may be made in this embodiment without departingfrom the principles and spirit of the invention, the scope of which isdefined in the claims and their equivalents.

What is claimed is:
 1. A defect management method, comprising: storingremainder state information for a spare area of a recording medium, theremainder state information indicating whether the spare area is notused, at least used a predetermined amount, and full; and performingdefect replacement based on the remainder state information.
 2. Thedefect management method of claim 1, further comprising allocating asupplementary spare area, after initialization of the recording mediumand before remainder state information for the spare area indicatesfull.
 3. The defect management method of claim 2, wherein the allocatingof the supplementary spare area is performed a plurality of times afterinitialization of the recording medium.
 4. The defect management methodof claim 2, wherein the allocating of the supplementary spare area isperformed in a forward direction from a rearmost portion of thesupplementary spare area.
 5. The defect management method of claim 1,wherein the size of the spare area is based on the number of defectsgenerated upon initialization of said recording medium.
 6. The defectmanagement method of claim 1, wherein the remainder state informationfor the spare area further indicates whether a supplementary spare areahas been allocated on the recording medium.
 7. The defect managementmethod of claim 1, further comprising storing, on the recording medium,information of a size and remainder state of a supplementary spare area,with the information of the size and remainder state of thesupplementary spare area being stored upon initialization of therecording medium.
 8. The defect management method of claim 1, furthercomprising storing, on the recording medium, remainder state informationfor a supplementary spare area selectively indicating whether asufficient amount of the supplementary spare area remains unused, atleast a predetermined amount of the supplementary spare area has beenused, and the supplementary spare area has been completely used.
 9. Adefect management method, comprising: performing defect management of arecording medium by selectively using a plurality of sectors in a sparearea as replacement sectors based on a predetermined designation that aparticular one of the plurality of sectors will not be used as a sparesector; and continuing the performing of the defect management even whenit is determined that the particular one sector is not to be used as aspare sector.
 10. The defect management method of claim 9, furthercomprising: allocating a primary spare area upon initialization of therecording medium; allocating and/or expanding a supplementary spare areaafter the initialization; and storing, on the recording medium,remainder state information for the primary and supplementary spareareas representing degrees of use of the primary and supplementary spareareas, respectively.
 11. The defect management method of claim 10,further comprising storing the remainder state information either in adefect management area or a disc definition structure area of therecording medium.
 12. The defect management method of claim 10, whereinthe remainder state information for the primary spare area selectivelyindicates whether a sufficient amount of the primary spare area remainsto manage defects, whether at least a predetermined amount of theprimary spare area has been used and no supplementary spare area hasbeen allocated, whether at least the predetermined amount of the primaryspare area has been used and the supplementary spare area has beenallocated, and whether the primary spare area has been completely used.